DP's instant cast component is very powerful, especially with heroism where you can almost keep casting it, waiting for the first tick and casting it again. This is probably only something you can do with T8 2set bonus though.

Hard refreshing SW:P through recasting it (as opposed to MF's soft refreshing it) can be useful when:- You possess a crit buff through Potion of Wild Magic and/or Nevermelting Ice Crystal.- You have a Rune of Power/Malygos Spark damage buff.- Your current SW:P wasn't casted with 5 stack Shadow Weaving.

During Heroism: Leave out MB from rotation, be sure to cast VT/DP as soon as it starts and just before it ends to get full benefit from the haste. Otherwise make use of any potions and MF the day away.